6 ways to heal trauma without medication | Bessel van der Kolk | Big Think

Trauma, in the body, can be understood as the chronic and persistent dysregulation of the nervous system due to overwhelming events or life circumstances. This reaction in the body occurs when an event happens in a way that the brain considers either “too much and too fast” (too much of something bad) or “too little and too late” (not enough of something good).

These events cause the body and brain to go into either a state of hyperarousal, meaning they get stuck in overdrive (fight/flight), or a state of hypoarousal, meaning they get stuck in nervous system shutdown (freeze).
Both hyperarousal and hypoarousal can cause wide and far-ranging mental and physiological side effects. Physical changes in the body due to trauma are known as somatic symptoms and are the basis of the Three Boards Model (Price, 1996).

https://www.psychologytoday.com/us/blog/the-body-knows-the-way-home/202104/how-do-we-heal-trauma